package com.interest.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

import org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBody;

import com.alibaba.fastjson.JSONObject;
import com.interest.bean.AccessToken;

public class SignUtil {
	// 与接口配置信息中的Token要一致
	private static String token = "afadf8909";
	
	private static String access_token_url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=#appid&secret=#secret";

	public static AccessToken getAccessToken(String appid, String appsecret) {
		AccessToken accessToken = null;
		String url = access_token_url.replace("#appid", appid).replace("#secret", appsecret);
		String resp = HttpConUtil.doGet(url);
		if (null != resp && !"".equals(resp)) {
			JSONObject respJson = JSONObject.parseObject(resp);
			String access_token = respJson.getString("access_token");
			int expires_in = respJson.getIntValue("expires_in");
			accessToken = new AccessToken();
			accessToken.setExpiresIn(expires_in);
			accessToken.setToken(access_token);
		}
		return accessToken;
	}

	public static boolean checkSign(String signature, String timestamp, String nonce) {
		String[] arr = new String[] { token, timestamp, nonce };
		// 将token、timestamp、nonce三个参数进行字典序排序
		Arrays.sort(arr);
		StringBuilder content = new StringBuilder();
		for (int i = 0; i < arr.length; i++) {
			content.append(arr[i]);
		}

		MessageDigest md = null;
		String tmpStr = null;

		try {
			md = MessageDigest.getInstance("SHA-1");
			// 将三个参数字符串拼接成一个字符串进行sha1加密
			byte[] digest = md.digest(content.toString().getBytes());
			tmpStr = byteToStr(digest);
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}
		content.setLength(0);
		// 将sha1加密后的字符串可与signature对比，标识该请求来源于微信
		return tmpStr != null ? tmpStr.equals(signature.toUpperCase()) : false;
	}

	/**
	 * 将字节数组转换为十六进制字符串
	 * 
	 * @param byteArray
	 * @return
	 */
	public static String byteToStr(byte[] byteArray) {
		String strDigest = "";
		for (int i = 0; i < byteArray.length; i++) {
			strDigest += byteToHexStr(byteArray[i]);
		}
		return strDigest;

	}

	/**
	 * 将字节转换为十六进制字符串
	 * 
	 * @param mByte
	 * @return
	 */
	private static String byteToHexStr(byte mByte) {
		char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
		char[] tempArr = new char[2];
		tempArr[0] = Digit[(mByte >>> 4) & 0X0F];
		tempArr[1] = Digit[mByte & 0X0F];

		String s = new String(tempArr);
		return s;
	}

}
